Analysis of Faraday–Michelson quantum key distribution system with unbalanced attenuation  

作　　者：宋萧天 李宏伟 张春梅 王东 王双 银振强 陈巍 韩正甫 

机构地区：[1]Key Laboratory of Quantum Information,CAS,University of Science and Technology of China [2]Synergetic Innovation Center of Quantum Information & Quantum Physics,University of Science and Technology of China

出　　处：《Chinese Optics Letters》2015年第1期88-92,共5页中国光学快报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.61101137,61201239,61205118,and 11304397);the China Postdoctoral Science Foundation(No.2013M540514)

摘　　要：Quantum key distribution （QKD） is a major research topic because it provides unconditional security. Unfortunately, many imperfections remain in QKD＇s experimental realization. The Faraday-Michelson （FM） QKD system is proposed to eliminate these imperfections using polarization. However, the long arm＇s phase modulator （PM） has an unexpected insertion loss, meaning that the state sent is no longer perfect. In this letter, we propose an alternative FM-QKD system structure, and analyze the security and key generation rate in comparison with the original system via different analysis methods. We find an obvious key rate improvement when the PM insertion loss is not extremely small.Quantum key distribution （QKD） is a major research topic because it provides unconditional security. Unfortunately, many imperfections remain in QKD＇s experimental realization. The Faraday-Michelson （FM） QKD system is proposed to eliminate these imperfections using polarization. However, the long arm＇s phase modulator （PM） has an unexpected insertion loss, meaning that the state sent is no longer perfect. In this letter, we propose an alternative FM-QKD system structure, and analyze the security and key generation rate in comparison with the original system via different analysis methods. We find an obvious key rate improvement when the PM insertion loss is not extremely small.

关 键 词：Insertion losses Phase modulation 

分 类 号：O413.1[理学—理论物理] TN918.4[理学—物理]